In the first episode of the 3rd season ("Tattoo"), the girls (Allison & Lydia) are driving down a lonely
stretch of rural road at night when they stop at a stoplight, only to find that their ex-boyfriends
(Scott & Stiles) are sitting in a car stopped next to them at the light. This is an awkward
situation, and they scramble to get away.

But then, just as Allison is considering talking to Scott, a stag suddenly comes out of
nowhere, running down the middle of the road, and smashes through the girls' windshield.

This scene was shot in L.A.'s San Fernando Valley, on Woodley Avenue, between
Victory Blvd (on the north) and Burbank Blvd (on the south), in Van Nuys.

That's where the Woodley passes through the Sepulveda Recreation Area, along the
west edge of Woodley Ave Park, around 6100 Woodley Ave.

The cars are heading northwest up Woodley, on the northeast side of the road.
The intersection where they are stopped on Woodley is at a small side road
which leads to the park's Donald Tillman Japanese Garden.

( The shot of the stag smashing through the windshield was, of course,
filmed at the Teen Wolf studio using green-screen/CGI. )